1. Field of the Invention
The present invention relates to a liquid container that utilizes negative pressure for supplying liquid to the members outside the liquid container, such as an ink discharge unit. The invention also relates to a method of manufacture therefor, an ink jet cartridge that uses such container, and an ink jet recording apparatus. More particularly, the invention relates to the field of ink jet recording to which is applicable an ink tank manufactured by blow molding the ink tank itself.
2. Related Background Art
In recent years, along with the miniaturization of an ink jet recording apparatus, an ink tank is installed on the carriage or a structure is adopted so that an ink tank unit is detachably installed on the recording head in order to reduce running costs.
An ink tank of the kind needs an airtight sealing to prevent ink leakage from the supply port when physically distributed for delivery or to prevent ink from being evaporated. As regards this sealing, it has been conventionally practiced in general to apply a sealing tape to or provide a cap member for the supply port portion.
In a case of the sealing arrangement of the kind, the user removes the sealing member when the ink tank is used. The sealing tape or the cap member thus removed is discarded as it is, thus presenting the problems related to environments and costs as well.
Also, depending on the sealing structure, there is still a possibility that ink leaks or ink evaporates due to the unexpected removal of a sealing member at the time of physical distribution for deliver.
It is an object of the present invention to provide a replaceable liquid container (ink tank) having a simple sealing structure capable of preventing ink leakage or the like at the time of distribution for delivery, and also, presenting no wasted substance when it is used.
It is another object of the invention to provide a method for manufacturing the liquid container for which the sealing structure thereof can be manufactured by a simple method at low costs.
It is still another object of the invention to provide an ink jet recording apparatus capable of mounting such liquid container thereon.
In order to achieve the objects described above, the liquid container of the present invention is substantially in a polyhedral form with the corners formed by the extended portions of the tree planes of the polyhedron, which comprises outer walls having strength to form a housing; inner walls having the outer plane equal to or analogous to the inner plane of the outer walls with the corners corresponding to the corners of the outer walls to form a liquid containing portion capable of containing liquid in the interior formed thereby, having strength smaller than that of the outer walls; and a liquid supply portion for supplying liquid contained in the liquid containing portion to the outside. Then, for this liquid container, the liquid supply portion is sealed only by the inner walls.
Also, the method of the present invention for manufacturing a liquid container formed by a polyhedral section, which is provided with outer walls having strength to form a housing; inner walls having the outer plane equal to or analogous to the inner plane of the outer walls with the corners corresponding to the corners of the outer walls to form a liquid containing portion capable of containing liquid in the interior formed thereby, having strength smaller than that of the outer walls; a liquid supply portion for supplying liquid contained in the liquid containing portion to the outside; and a liquid injection inlet for injecting liquid into the liquid containing portion, comprises the steps of preparing a first parison for use of the first walls and a second parison for use of the outer walls; forming the inner walls and the outer walls to be substantially analogous by injecting the air inside to expand the first and second parisons along dies; peeling off the inner walls from the outer walls; and forming the liquid supply portion by cutting a part of the outer walls.
Also, in order to achieve the objects described above, the present invention provides an ink jet cartridge that uses the aforesaid container, as well as an ink jet recording apparatus.
The ink jet cartridge of the present invention comprises a liquid container for containing liquid; and a recording head unit connected with the liquid container for discharging liquid in accordance with recording signals. Then, for this ink jet cartridge, the recording head unit is provided with a recording head for discharging liquid; a chamber for containing a negative pressure generating member having a liquid supply portion for supplying liquid to the recording head, and an atmospheric communication unit communicated with the air outside to contain therein a negative pressure generating member capable of retaining liquid in the interior thereof, and also, the liquid container is provided with outer walls in a substantially polyhedral form, having corners formed by extended portions of the three planes of the polyhedron, at the same time, having strength to form a housing; inner walls having the outer plane equal to or analogous to the inner plane of the outer walls with the corners corresponding to the corners of the outer walls to form a liquid containing portion capable of containing liquid in the interior formed thereby, having strength smaller than that of the outer walls; and a liquid supply portion for supplying liquid contained in the liquid containing portion to the outside. This liquid supply portion is sealed only by the inner walls, and at the same time, the liquid container is made attachable to and detachable from the chamber for containing a negative pressure generating member.
Also, the ink jet recording apparatus of the present invention comprises an ink jet cartridge provided with a liquid container for containing liquid, and a recording head unit connected with the liquid container for discharging liquid in accordance with recording signals; and a carriage having the cartridge detachable mounted thereon to perform scanning. For this ink jet recording apparatus, the liquid container is provided with outer walls in a substantially polyhedral form, having corners formed by extended portions of the three planes of the polyhedron, at the same time, having strength to form a housing; inner walls having the outer plane equal to or analogous to the inner plane of the outer walls with the corners corresponding to the corners of the outer walls to form a liquid containing portion capable of containing liquid in the interior formed thereby, having strength smaller than that of the outer walls; and a liquid supply portion for supplying liquid contained in the liquid containing portion to the outside. This liquid supply portion is sealed only by the inner walls, and at the same time, when the liquid container is installed on the recording head, the detaching thereof from the recording head is prohibited until liquid in the interior thereof is no longer present.
In accordance with the present invention structured as described above, the liquid supply port, through which liquid contained in the liquid containing portion is supplied to the outside, is sealed only by the inner walls that form the liquid containing portion. Therefore, when the liquid container is installed on the recording head, the inner walls of the liquid supply port are broken by the ink supply tube provided for the recording head. Thereafter, it is prohibited to detach the liquid container and the recording head until liquid in the liquid container no longer exists.
Thus, it becomes possible to prevent liquid leakage without the sealing tape, cap, or the like to be used for the liquid container at the time of distribution for delivery. Also, the liquid leakage is prevented when the liquid container is used, because the detachment of the liquid container and the recording head is prohibited until liquid in the container no longer exits.